Turret indexing mechanism

ABSTRACT

A pneumatic-hydraulic control is coupled with either a manually or numerically controlled punch press to rotate the turrets of the press to the proper positions. Pneumatic pressure is directed selectively to one of two fluid accumulators to force fluid from that accumulator through an open deceleration valve to drive a piston which in turn is coupled to a rack and pinion drive for rotating the turrets. The other side of the piston is exhausted through an open deceleration valve to the other fluid accumulator. A slider switch having a central stop contactor and two deceleration contactors is secured to the rack and moves with the rack across a linear multi-contact slidebar. One of the contactors on the slidebar corresponding with the desired station on the turret is energized. A deceleration contactor engaging the energized contact closes the deceleration valve of the driving fluid accumulator forcing the fluid to go through a restricted passage thus decelerating the turret drive. The stop contactor engaging the energized contact exhausts both fluid accumulators to stop the turret drive.

United States Patent Daniels 1 Aug. 29, 1972 1541 TURRET INDEXINGMECHANISM 72 Inventor: Dennis Daniels,Williamsville,N.Y. [73] Assignee:U.S. Amada, Ltd., Seattle,- Wash.

22 Filed: Feb. 19,1971

21 Appl.No.: 112,859

[52] US. Cl. ..83/55l, 83/71, 83/552, 83/559 [51] Int. Cl. ..B26d 5/04[58] Field of Search ..83/55l, 552, 559, 71

[56] References Cited UNITED STATES PATENTS 3,377,887 4/1968 Nelson eta1 ..83/552 X 3,449,991 6/1969 Daniels ..83/552 X 3,527,130 9/1970Knehans ..83/552 X Pn'mary ExaminerFrank T. Yost Att0meySeed, Berry &Dowrey ABSTRACT A pneumatic-hydraulic control is coupled with either amanually or numerically controlled punch press to rotate the turrets ofthe press to the proper positions. Pneumatic pressure is directedselectively to one of two fluid accumulators to force fluid from thataccumulator through an open deceleration valve to drive a piston whichin turn is coupled to a rack and pinion drive for rotating the turrets.The other side of the piston is exhausted through an open decelerationvalve to the other fluid accumulator. A slider switch having a centralstop contactor and two deceleration contactors is secured to the rackand moves with the rack across a linear multi-contact slidebar. One ofthe contactors on the slidebar corresponding with the desired station onthe turret is energized. A deceleration contactor engaging the energizedcontact closes the deceleration valve of the driving fluid accumulatorforcing the fluid to go through a restricted passage thus deceleratingthe turret drive. The stop contactor engaging the energized contactexhausts both fluid accumulators to stop the turret drive.

5Claims,3DrawingFigures PATENTEDwczs m2 3,686,992

INVENTOR. DENNIS DANIELS ATTORNEYS TURRET INDEXING MECHANISM BACKGROUNDOF THE INVENTION 1. Field of the Invention This invention pertains topunch presses and particu larly to the control and indexing mechanismfor positioning the turrets of punch presses.

2. Description of the Prior Art The turrets as used with punch pressesinclude two co-axially aligned circular discs, each having its ownindependent axle and bearing housing on which they rotate. The discs arepositioned apart from each other to allow the work-piece which is to bepunched to pass between. The upper disc is the punch carrier and thelower disc is a die carrier.

At the time of punching the related punches and dies are preciselyaligned by means of shot-pins acting into bushings in the circulardiscs. The bushings are so placed to correspond to each radial stationof the turrets. Therefore, to drive the turrets around to the selectedposition, first the shot-pins must be withdrawn, and then through amotor and transmission arrangement rotation will take place. The twocommon methods heretofore used to obtain this motion are: (1) anelectrical motor with clutch arrangement and (2) an hydraulic motor withrelated control valves and pump drive system.

To achieve the necessary high speed turret index dictated by modern NCcontrols, it is necessary to rotate the turrets at a very high speed,which puts a heavy burden on the deceleration factors prior to reachingfinal position.

SUMMARY OF THE INVENTION It is an object of this invention to provide atechnique for rapidly indexing punching turrets.

It is another object of this invention to provide an apparatus forindexing turrets by the use of inexpensive and readily available shoppneumatic pressure.

It is another object of this invention to provide a turret indexingapparatus which combines readily available shop pneumatic pressure withmore readily controllable hydraulic fluid to control the speed andamount of rotation of punching turrets.

Basically the apparatus includes control means for directing pneumaticpressure to one of two fluid accumulators. The pressurized fluidaccumulator drives fluid through an open deceleration valve to a pistonwhich in turn is coupled to a turret rotating means. Station approachsensing means are coupled to the turret rotating means to sense theoncoming presence of a position command signal associated with aparticular station on the turrets to close the deceleration valve on thedriving fluid accumulator, forcing the fluid through a restrictedpassageway to decelerate the turret drive means. Next a stop sensingsignal is transmitted by the position command signal to exhaust bothfluid accumulators thus stopping'the turret drive means. The shotpinsmay then be placed in the turrets to finalize the position and lock theturrets in place.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective of a punchpress embodying the principles of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 illustrates aconventional C-frame punch press 10 having a work-piece holder 12 andwork-piece positioning means 14. The punch press is provided with a pairof turrets 16 which rotatably position a variety of tools beneath thestriker on the punch press.

The turrets include an upper disc 20 and a lower disc 21 eachrespectively mounted by its own axle and bearings 23 and 24. The upperdisc 20 contains a plurality of circumferentially spaced punches 26whereas the lower disc includes a plurality of circumferentially spaceddies 28 alignable beneath the punches 26. The discs are locked andaccurately positioned in place by shot-pins 30 acting in a conventionalmanner in bushings 32 corresponding to the various stations'on theturrets.

The indexing mechanism of this invention includes a solenoid actuatedspring-centered four-way rotation valve 38 movable into the lefthand andrighthand position, respectively, by solenoids 39 and 40. Air at readilyavailable shop pressures is introduced through an intake line 42 and isexhausted through an exhaust line 44. The valve is coupled to a pair ofaccumulators 46 and 48 each containing a quantity of hydraulic fluid F.Fluid accumulator 46 has a lower passageway 50 connected to a bypass leg52 in which is positioned a manually-controlled conventional flowcontrol valve 54. A solenoid controlled deceleration valve56 ispositioned in the lower passageway in parallel with the bypass leg. Thelower passageway connects to one end of an hydraulic cylinder 58.

The other accumulator 48 is provided with a lower passageway 60 having abypass leg 62 in which is positioned a conventional manual flow controlvalve 64. A solenoid controlled deceleration valve 66 is provided in thelower passageway in parallel with the flow control valve 64. The lowerpassageway 60 is connected to the other end of the cylinder 58.

A piston 70 is slidably received in the cylinder 58 and g is secured toa piston rod 72 which in turn is secured to a plate 74. In the preferredform of the invention, as illustrated in FIG. 2, the plate 74 is rigidlysecured to a rack and pinion drive 76 coupled to the axles 23 and 24 ofthe turrets. Thus reciprocation of the piston 70 will simultaneouslyrotate the two turrets. The stroke of the piston will be equivalent to360 of rotation of the turrets.

A slide switch 80 is rigidly secured to the rack of the top turret forlinear movement along a slidebar 82. The slide switch is provided with acentral stop contactor 84 and two spaced deceleration contactors 85 and86. The slidebar is provided with a plurality of spaced position commandcontacts 88 each corresponding to a station on the turrets and eachelectrically coupled to either a NC control 90 or a manual control 91.Engagement of the energized position command contact by one ofcontactors will complete a circuit for operating the variousdeceleration valves and the rotation valve 38.

In operation the leading deceleration contactor 85 or 86, depending uponthe direction of movement of the piston 70, will first engage theenergized position command contact 88. At this point an electricalsignal is transmitted to a deceleration valve closing the valve to forcethe fluid in the lower passageway through the related flow control valveto reduce the rate of movement of the piston 70. The central stopcontactor then engages the energized position command contact at thedecelerated rate and signals the rotation control valve to return to itscenter exhaust position so that the piston is stopped. The shot-pins 30may then be driven into the bushings 32 to align and position theturrets at the proper station.

As a typical example assume the position command contact 88 furthest tothe left in FIG. 2 is energized. The numerical control will alsoenergize the solenoid 40 directing air through line 42 to theaccumulator 48. Hydraulic fluid F will be forced through theunrestricted lower passageway 60 to therighthand side of the cylinder 58driving the piston and thus the racks of the rack and pinion drive 76also to the left. When the contactor 86 makes contact with the energizedcontact 88 a signal will be sent to close the deceleration valve 66forcing the fluid through the bypass leg 62 and flow control valve 64.Since the rate of flow is reduced the piston will decelerate but willcontinue moving to the left. Next the central stop contactor 84 willengage the energized contact signally the rotation valve to return toits center position so that all motion stops. Then the shot-pin may beinserted in the bushings as earlier described.

FIG. 3 illustrates a modified form of drive for rotating the turrets and21..In this form of the apparatus a conventional rotary actuator 158 isconnected to the lower passageways 50 and 60. The rotary actuator is ofthe type suitable for two way rotation. The rotary shaft 172 of therotary actuator is coupled to a belt and sprocket drive 176 which iscoupled to the axles 23 and 24 of the turrets. A slideswitch 80 engagesa slidebar 82 in the same manner as in the preferred embodiment.

Although the preferred forms of the invention have been illustrated anddescribed it should be understood that the apparatus is capable ofmodification by one skilled in the art without departing from theprinciples of the invention. Accordingly, the scope of the invention isto be limited only by the literal interpretation of the claims appendedhereto.

I claim:

1. In a punch press having a pair of turrets provided withcircumferentially spaced stations positionable beneath a punch striker,a turret indexing mechanism comprising drive means for rotating theturrets simultaneously to position a selected station beneath the punchstriker, said drive means including a pair of fluid accumulators eachhaving a reservoir of hydraulic fluid and an upper end for receivingpressurized air, control means coupled to each accumulator upper end forselectively pressurizing or exhausting the air on the hydraulic fluid,an hydraulic actuator having a powered member for rotating the turrets,means coupling the hydraulic fluid in said accumulators with saidhydraulic actuator for moving said powered member selectively inopposite directions, flow control means in said cou in means 0 erable trestrict the flow of fluid ther m, rst mean s for sensing the closeapproach of a station on the turrets to a punching position and operableto energize said flow control means for decelerating the powered memberand for sensing the presence of a station on the turret at the punchlocation for stopping said powered member thus stopping said stationbeneath the punching position.

' 2. The punch press of claim 1 said coupling means in- I cluding alower fluid passageway connected to each accumulator and having a bypassleg, a deceleration control valve in said passageway and variablerestriction valve in said bypasses in parallel with said decelerationvalve, said sensing means for sensing the close approach of a station tothepunch location being operable to energize said deceleration valve forforcing the flow through the flow restriction valve in the bypass leg.

3. The punch press of claim 1 wherein said hydraulic actuator is alinear cylinder and said powered means includes a piston and piston rodwithin said cylinder.

4. The punch press of claim 1 said hydraulic actuator including a rotaryactuator, said powered means including a rotary output shaft of saidrotary actuator.

5. The punch press of claim 1 said sensing means including a switchcoupled to said powered member and having a central stop contactor andtwo deceleration contactors, a slider bar having a plurality of spacedcontacts corresponding to the various stations of the turrets whenpositioned beneath the punch striker, the leading decelerationcontactor, dependent upon the direction of travel of the powered member,first con-

1. In a punch press having a pair of turrets provided withcircumferentially spaced stations positionable beneath a punch striker,a turret indexing mechanism comprising drive means for rotating theturrets simultaneously to position a selected station beneath the punchstriker, said drive means including a pair of fluid accumulators eachhaving a reservoir of hydraulic fluid and an upper end for receivingpressurized air, control means coupled to each accumulator upper end forselectively pressurizing or exhausting the air on the hydraulic fluid,an hydraulic actuator having a powered member for rotating the turrets,means coupling the hydraulic fluid in said accumulators with saidhydraulic actuator for moving said powered member selectively inopposite directions, flow control means in said coupling means operableto restrict the flow of fluid therein, first means for sensing the closeapproach of a station on the turrets to a punching position and operableto energize said flow control means for decelerating the powered memberand for sensing the presence of a station on the turret at the punchlocation for stopping said powered member thus stopping said stationbeneath the punching position.
 2. The punch press of claim 1 saidcoupling means including a lower fluid passageway connected to eachaccumulator and having a bypass leg, a deceleration control valve insaid passageway and variable restriction valve in said bypasses inparallel with said deceleration valve, said sensing means for sensingthe close approach of a station to the punch location being operable toenergize said deceleration valve for forcing the flow through the flowrestriction valve in the bypass leg.
 3. The punch press of claim 1wherein said hydraulic actuator is a linear cylinder and said poweredmeans includes a piston and piston rod within said cylinder.
 4. Thepunch press of claim 1 said hydraulic actuator including a rotaryactuator, said powered means including a rotary output shaft of saidrotary actuator.
 5. The punch press of claim 1 said sensing meansincluding a switch coupled to said powered member and having a centralstop contactor and two deceleration contactors, a slider bar having aplurality of spaced contacts corresponding to the various stations ofthe turrets when positioned beneath the punch striker, the leadingdeceleration contactor, dependent upon the direction of travel of thepowered member, first contacting the energized contact to signal theapproach of the station beneath the punch striker, and said central stopcontactor being operable to engage the energized contact fordeenergizing said control means to exhaust the air in both accumulatorsto stop said powered means.